Cellulitis is an inflammation of the subcutaneous tissue characterized by invasion without definite localization. Thin exudate spreads through the cleavage planes of tissue spaces. It usually involves the extremities and identifiable portal of entry is detectable. The most common etiologic organisms are Beta hemolytic streptococci, Staphylococci, Clostridium perfringens.
The invasiveness of this organism is due to the production of hyaluronidase and streptokinase, which dissolve the intercellular matrix and the fibrin inflammatory barrier respectively. Characteristically, the skin is dark red with local oedema and heat; it blanches on pressure. There may be vesicles and, in severe cases, cutaneous gangrene. Cellulitis is often accompanied by lymphangitis and lymphadenitis, and there may be an associated septicaemia.
There is usually an identifiable portal of entry which can be a surgical wound, puncture site, skin ulcer or dermatitis. Other features include:
- Local signs of inflammation, which may be very intense
- Poorly defined brown-red edema
- Blebs and bullae in severe cases; tissue destruction and ulceration may follow
- Central necrosis and suppuration may occur late in some complicated cases
- Systemic signs of bacteremia and toxemia due to spread and toxin release
- Rest to limit spread of infection and pain
- Elevation of the involved limb
- Hot, wet pack
- High dose broad spectrum antibiotics IV